/************************************************************************************

Filename    :   OVR_Linux_DeviceManager.h
Content     :   Linux-specific DeviceManager header.
Created     :   
Authors     :   

Copyright   :   Copyright 2013 Oculus VR, Inc. All Rights reserved.

Licensed under the Oculus VR SDK License Version 2.0 (the "License"); 
you may not use the Oculus VR SDK except in compliance with the License, 
which is provided at the time of installation or download, or which 
otherwise accompanies this software in either electronic or hard copy form.

You may obtain a copy of the License at

http://www.oculusvr.com/licenses/LICENSE-2.0 

Unless required by applicable law or agreed to in writing, the Oculus VR SDK 
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

*************************************************************************************/

#ifndef OVR_Linux_DeviceManager_h
#define OVR_Linux_DeviceManager_h

#include "OVR_DeviceImpl.h"

#include <unistd.h>
#include <sys/poll.h>


namespace OVR { namespace Linux {

class DeviceManagerThread;

//-------------------------------------------------------------------------------------
// ***** Linux DeviceManager

class DeviceManager : public DeviceManagerImpl
{
public:
    DeviceManager();
    ~DeviceManager();

    // Initialize/Shutdowncreate and shutdown manger thread.
    virtual bool Initialize(DeviceBase* parent);
    virtual void Shutdown();

    virtual ThreadCommandQueue* GetThreadQueue();
    virtual ThreadId GetThreadId() const;

    virtual DeviceEnumerator<> EnumerateDevicesEx(const DeviceEnumerationArgs& args);    

    virtual bool  GetDeviceInfo(DeviceInfo* info) const;

    Ptr<DeviceManagerThread> pThread;
};

//-------------------------------------------------------------------------------------
// ***** Device Manager Background Thread

class DeviceManagerThread : public Thread, public ThreadCommandQueue
{
    friend class DeviceManager;
    enum { ThreadStackSize = 64 * 1024 };
public:
    DeviceManagerThread();
    ~DeviceManagerThread();

    virtual int Run();

    // ThreadCommandQueue notifications for CommandEvent handling.
    virtual void OnPushNonEmpty_Locked() { write(CommandFd[1], this, 1); }
    virtual void OnPopEmpty_Locked()     { }

    class Notifier
    {
    public:
        // Called when I/O is received
        virtual void OnEvent(int i, int fd) = 0;

        // Called when timing ticks are updated.
        // Returns the largest number of microseconds this function can
        // wait till next call.
        virtual UInt64  OnTicks(UInt64 ticksMks)
        {
            OVR_UNUSED1(ticksMks);
            return Timer::MksPerSecond * 1000;
        }
    };

    // Add I/O notifier
    bool AddSelectFd(Notifier* notify, int fd);
    bool RemoveSelectFd(Notifier* notify, int fd);

    // Add notifier that will be called at regular intervals.
    bool AddTicksNotifier(Notifier* notify);
    bool RemoveTicksNotifier(Notifier* notify);

private:
    
    bool threadInitialized() { return CommandFd[0] != 0; }

    // pipe used to signal commands
    int CommandFd[2];

    Array<struct pollfd>    PollFds;
    Array<Notifier*>        FdNotifiers;

    Event                   StartupEvent;

    // Ticks notifiers - used for time-dependent events such as keep-alive.
    Array<Notifier*>        TicksNotifiers;
};

}} // namespace Linux::OVR

#endif // OVR_Linux_DeviceManager_h